利用光谱反射率预测烤烟叶片烟碱含量

Predicting leaf nicotine content of flue-cured tobacco using hyperspectral reflectance

以ASD Field spec FR 2500光谱仪测定了不同生育期不同氮钾处理的烤烟叶片光谱反射率,通过光谱反射率、一阶导数光谱和光谱特征变量与烟碱含量的相关分析和逐步回归模型筛选出特征波长,并对回归模型的预测效果进行检验。结果表明,一阶导数光谱回归方程预测效果最好、光谱反射率回归方程次之、特征变量回归方程最差。筛选出光谱反射率特征波长为1792nm、一阶导数光谱特征波长为810nm。光谱反射率和一阶导数光谱在427～712、741～810、1382～1879、1905～1969、2067～2338nm范围内与烟碱含量相关性强。本研究为采用高光谱技术预测烟叶烟碱含量提供了理论参考。

Hyperspectral reflectances of flue-cured tobacco leaves were measured with ASD Field spec FR 2500 during different growth stages in different nitrogen, potassium treatments. Characteristic wavelengths were picked out through the correlations between nicotine and spectra reflectance, the first derivative spectra, spectral characteristic variables and the stepwise regression models. And the predicting effects of models were tested by the correlations between predicted values and mensurated values. The results showed that the first derivative spectra regression equation had the best predicting effect, and the spectra reflectance had better predicting effect, and the spectral characteristic variables had the worst predicting effect. The characteristic wavelength of spectra reflectance was 1792 nm and that of the first derivative spectra was 810 nm. The spectra reflectance and the first derivative spectra had an intimate relationship with nicotine content in 427-712, 741-810, 1382-1879, 1905-1969 and 2067-2338 nm. Accordingly, this study suggests that spectral data serve as promising measures to predict the nicotine content of tobacco leaves.